Surface Protective Structure

ABSTRACT

Not only when tableware and vessels have a point contact, but also when they have a surface contact and line contact, abrasions caused thereby are made visually less noticeable and performance of cleaning soil deposited on the surface is improved. 
     In a surface protection structure for protecting the surface of a water-depositable member, such as the sink of a system kitchen, an embossed pattern is formed by a plurality of hemispherical projections protrusively provided on a smooth bottom face, and the embossed pattern is subjected to surface finishing with good removing property of stains. At this time, an interval between those projections which are adjoining in at least one direction and/or an interval between those projections which are adjoining in another direction orthogonal to the one direction may be set to 2.0 to 10.0 mm.

TECHNICAL FIELD

The present invention relates to a surface protection structure for protecting the surface of a water-depositable member, such as the sink of a system kitchen.

BACKGROUND ART

FIG. 1 is a perspective view showing an ordinary system kitchen. As shown in FIG. 1, a system kitchen 50 placed in a kitchen has a sink cabinet 51, a range cabinet 52 placed adjacent thereto, and a single top plate 53 which covers them. In the system kitchen 50, a deep-drawn sink 54 is formed at the center portion of a sink area A of the worktop 53, which covers the sink cabinet 51, and hot water is supplied to the sink 54 from a faucet 61. A rectangular opening 56 is cut out in a frontward portion of a range area B of the worktop 53, which covers the range cabinet 52, and a single range 55 is dropped in over the range cabinet 52 from the opening 56. Further, formed on the worktop 53 between the sink area A and the range area B is a cooking table unit area C where a user cooks foods and places tools necessary for cooking, tableware and the like.

The sink 54 is produced by press forming a stainless steel plate. In general, because a stainless steel plate has an excellent corrosion resistance and appears clean, it is widely used under environments where water is frequently used, particularly, in the sink of a system kitchen, a bathtub and so forth.

The user of the system kitchen 50 washes various kinds of tableware, vessels and the like in the sink 54. The materials for tableware, vessels and the like which are washed include various kinds of resins, ceramics, glass and the like. Further, in a case of washing pans, spoons and the like likewise, the materials include aluminum, copper, iron, stainless steel and the like.

Generally, stainless steel of which the sink 54 is made has a lower hardness than ceramics, glass and the like of which the aforementioned tableware, vessels and the like to be washed are made. When the tableware, vessels and the like contact the sink 54, therefore, various scratches, such as abrasions, scrapes, and grazes, are made on the surface of the sink 54. Because the sink 54 of the conventional system kitchen 50 has a very smooth surface, such scratches become visually noticeable.

At the time of washing tableware, vessels and the like, water drops are deposited on individual portions of the sink 54, and contain a part of stain of tableware, vessels and the like which have been washed and a substance like detergent or the like. Further, tap water contains a small amount of a substance, such as calcium hydroxide and magnesium. When water drops deposited on the sink 54 at the time of washing are dried, therefore, those portions become blemishes remaining as stained spots. This degrades the clean appearance of the sink 54.

To overcome these problems, a stainless steel plate having the abrasion resistance and stain resistance improved by specific minute convexoconcaves provided at random on the surface of the stainless steel plate which is adapted to the sink 54 has been conventionally proposed (see Patent Document 1, for example).

For the abrasion resistance and prevention of staining from being caused by deposition of water drops or the like on the surface, the stainless steel plate described in the Patent Document 1 has convexoconcaves protrusively provided in the rolling direction within a height range of 3 to 50 μm and a range of 20 to 1000 convexoconcaves per length of 25.4 mm. This can make it hard for abrasions and stains to be put on the stainless steel plate or can make abrasions and stains visually less noticeable.

Conventionally, there has been proposed a sink plate-like article which has a plate-like body with an embossed pattern provided on the surface thereof by a stainless steel plate and has an enamel layer with an embossed pattern provided on the surface of the plate-like body (see Patent Document 2, for example). In Patent Document 2, the aforementioned abrasions made by various tableware, vessels and the like are put on the projections of the embossed pattern on the enamel layer on the surface. Because the projections of the embossed pattern are discontinuous, abrasions to be put on the projections also become discontinuous, resulting in that abrasions can be made visually less noticeable.

Conventionally, there also has been proposed a tank device for a tank-equipped cabinet which has variable designs due to a convexoconcave pattern formed at the main portion of the outer faces of the tank (see Patent Document 3, for example).

[Patent Document 1] Japanese Unexamined Patent Publication No. 2004-137796

[Patent Document 2] Japanese Unexamined Utility Model Publication No. Hei 1-74266

[Patent Document 3] Japanese Unexamined Patent Publication No. Hei 8-84676

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

However, the disclosed technique described in the Patent Document 1 forms convexoconcaves of the micron order on a stainless steel plate, and thus has a problem such that while abrasions made by point contact of tableware, vessels and the like can be made less noticeable, abrasions made by surface contact or line contact thereof cannot be made less noticeable. In a case of removing stains deposited on a stainless steel plate, the stains are scrubbed with a kitchen sponge having fibers of nylon or the like adhered to the surface layer, but the stain removing performance depends on the pitch and height of the convexoconcaves on the stainless steel plate with respect to the size of the fibers adhered to the kitchen sponge. When the convexoconcaves on the surface are on the micron order, therefore, deposited stains cannot be removed effectively.

With the sink plate-like article disclosed in the Patent Document 2, abrasions are likely to stand out for the enamel layer is colored, and an oxide film is easily formed on the surface of the stainless steel plate for the enamel layer has a high baking temperature. Further, when separation of the enamel layer progresses due to chips, abrasions or the like, such separation may be considered as a repair target even if there is no problem in view of the quality of the sink.

That is, in addition to the problem that abrasions made by surface contact or line contact are made visually noticeable, the sink plate-like article disclosed in the Patent Document 2 has a problem such that the texture of stainless steel cannot be obtained so that a user cannot feel clean.

Likewise, the tank device for a tank-equipped cabinet disclosed in the Patent Document 3 has the problem that abrasions made by surface contact or line contact become noticeable.

Accordingly, the invention has been designed in consideration of the aforementioned problems, and is directed to provide a surface protection structure which can make abrasions, caused by point contact, surface contact or line contact of tableware, vessels and the like, visually less noticeable not only when the tableware and vessels have the point contact, but also when they have the surface contact or line contact, and can improve the performance of cleaning stain deposited on the surface.

Means for Solving the Problems

The present inventor has invented a surface protection structure having an embossed pattern formed by a plurality of hemispherical projections protrusively provided on the smooth surface of a member.

That is, a surface protection structure according to claim 1 of the invention is a surface protection structure for protecting a surface of a water-depositable member, wherein an embossed pattern is formed by a plurality of hemispherical projections protrusively provided on the smooth surface of the member, and the embossed pattern is subjected to surface finishing for good stain removal performance.

A surface protection structure according to claim 2 of the invention is the surface protection structure as set forth in claim 1, wherein tops of the projections have a height of 0.05 to 1.0 mm to the surface of the member, and an interval between those projections which are adjoining in at least one direction is 2.0 to 10.0 mm.

Further, a surface protection structure according to claim 3 of the invention is the surface protection structure as set forth in claim 2, wherein an interval between those projections which are adjoining in another direction orthogonal to the one direction is 2.0 to 10.0 mm.

Furthermore, a surface protection structure according to claim 4 of the invention is the surface protection structure as set forth in claim 3, wherein an interval between those projections which are adjoining in a direction other than the one direction and the another direction is less than 2.0 mm.

Moreover, a surface protection structure according to claim 5 of the invention is the surface protection structure as set forth in any one of claims 1 to 4, wherein the surface protection structure is adapted to a kitchen member.

Further, a surface protection structure according to claim 6 of the invention is the surface protection structure as set forth in claim 5, wherein the kitchen member is made of stainless steel.

Furthermore, a surface protection structure according to claim 7 of the invention is the surface protection structure as set forth in claim 5 or 6, wherein the embossed pattern is formed at least at a bottom face of a sink, and a margin portion with no convexoconcaves is provided in a contiguous area between at least one of a drain and a circumferential wall of the sink and the embossed pattern.

Moreover, a surface protection structure according to claim 8 of the invention is the surface protection structure as set forth in claim 7, wherein a translucent film is laminated on the embossed pattern.

A surface protection structure according to claim 9 of the invention is a surface protection structure for protecting a surface of a water-depositable member, wherein an embossed pattern is formed by a plurality of hemispherical projections protrusively provided on the smooth surface of the member, the embossed pattern is subjected to surface finishing with good stain removing performance, and each of the projections is in point contact with an object to be contacted.

EFFECT OF THE INVENTION

According to the invention, an embossed pattern is formed by a plurality of hemispherical projections protrusively provided on a smooth member surface, tableware, vessels and the like contact the embossed pattern at a single point of the top of each projection, and do not have line or surface contact with the projections. Because abrasions caused by such a contact can be dispersed like dots, they can be made less noticeable visually. Further, according to the invention, cleaning property of stains deposited on the surface can be improved by performing surface finishing with good stain removing performance on the embossed pattern.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing an ordinary system kitchen.

FIG. 2 is a perspective view showing the structure of a system kitchen provided with a sink to which the invention is adapted.

FIG. 3 is a top view of a sink 1 shown in FIG. 2.

FIG. 4 is an enlarged view of an area F shown in FIG. 3.

FIGS. 5( a)-5(c) are exemplary diagrams showing examples of patterns of an embossed pattern 41.

FIG. 6( a) is a cross-sectional view of the embossed pattern 41 in a horizontal direction x, and FIG. 6( b) is a cross-sectional view in a vertical direction y.

FIG. 7 is a graph showing the relationship between the height of projections 25 and the durability with the number of wears taken on the horizontal axis and the height H of the projections 25 taken on the vertical axis.

DESCRIPTION OF REFERENCE NUMERALS

-   -   1, 54 sink     -   2, 50 system kitchen     -   11 cabinet     -   13, 53 top plate     -   14 a recessed portion     -   14 b drain     -   15 faucet     -   17 cock     -   25 projections     -   26 flat portions     -   28 hydrophilic film     -   30 margin portion     -   31 circumferential wall     -   41 embossed pattern     -   42 bottom face     -   51 sink cabinet     -   52 range cabinet     -   55 range     -   56 opening     -   61 faucet     -   A sink area     -   B range area     -   C cooking table unit area

BEST MODE FOR CARRYING OUT THE INVENTION

As an example of the best mode for carrying out the invention, a sink in a system kitchen to be used at the time of cooking food in a restaurant, home or the like will be described in detail with reference to the accompanying drawings.

FIG. 2 is a perspective view showing the structure of a system kitchen provided with a sink to which the invention is adapted. As shown in FIG. 2, a sink 1 to which the invention is adapted is provided in a system kitchen 2 having at least a worktop or a counter (hereinafter they will be called “top plate”). The system kitchen 2 has a cabinet 11, and a top plate 13 covering the top surface of the cabinet 11, with the deep-drawn sink 1 disposed at the center portion of a sink area A adjoining to a cooking table unit area of the top plate 13. Further, the system kitchen 2 is provided with a faucet 15 for feeding hot water to the sink 1.

Cooking appliances (not shown), such as a juicer and rice boiler, which are necessary to cook food materials, as well as a chopping-board (not shown) or the like for processing the materials are placed on the cooking table unit area C of the top plate 13. Because metal cooking containers to be heated in use, such as a pan and oven, can also be placed on the top plate 13, the top plate 13 needs to be made of a material which is excellent in heat resistance, shock resistance, chemical resistance and mechanical strength, and is normally made of heat-resistant glass, ceramics, stainless steel, artificial marble or the like.

The faucet 15 lets water or hot water to flow out into the sink 1 from a cock 17 according to the turning operation by a user. This can allow for cooking in the sink 1 while letting water flow from the cock 17. When water is not let to flow out, the cock 17 can be turned in a direction E shown in FIG. 2. This can permit cooking using the wide interior of the sink 1 without interference of the cock 17.

A recessed portion 14 a for water draining is formed at the peripheral portion of the sink 1, and a drain 14 b is provided at a bottom face 42. The recessed portion 14 a and the drain 14 b of the sink 1 are integrally formed by methods such as press molding, cast molding and injection molding. While the material for the sink 1 is not particularly limited, metal materials, such as heat-resistant resin and stainless steel plate, can be used.

Further, an embossed pattern 41 is formed at the bottom face 42 of the sink 1. FIG. 3 is a top view of the sink 1 shown in FIG. 2, and FIG. 4 is an enlarged view of an area F shown in FIG. 3. FIGS. 5( a) to 5(c) are exemplary diagrams showing examples of patterns of the embossed pattern 41. FIG. 3 shows the area where the embossed pattern 41 is formed (embossed pattern forming area) in hatched lines. The embossed pattern 41 in the invention is not limited to a case where it is formed over the entire bottom face 42, but needs to be formed only at a part of the bottom face 42.

As shown in FIG. 4, the embossed pattern 41 has a plurality of projections 25 protrusively provided at the smooth bottom face 42. In the following description, the plurality of projections 25 together with flat portions 26 between the individual projections 25 are called the embossed pattern 41. While it is desirable that the projections 25 be laid out regularly in a horizontal direction x and a vertical direction y of the bottom face 42 as shown in, for example, FIG. 5( a) and FIG. 5( b), the invention is not limited to this case and a plurality of projections 25 may be formed discretely as shown in FIG. 5( c). It is to be noted that because the embossed pattern 41 is formed at a position visible by the user, it is desirable that the pattern formed should not cause the collection of the projections 25 to give visually awkward feeling when the design needs to be maintained even in a case where the projections 25 are formed discretely. This can eliminate the visual awkwardness the user of the system kitchen 2 would otherwise feel by the embossed pattern 41 formed by the collection of the projections 25.

It is desirable that as shown in FIG. 3, a smooth margin portion 30 without convexoconcaves be provided between the drain 14 b of the sink 1 and/or the circumferential wall 31 and the embossed pattern 41, i.e., in a contiguous area around the embossed pattern 41. The width of the margin portion 30 is such that a width G from the periphery of the area where the embossed pattern 41 is formed to the drain 14 b is, for example, 8 mm, and a width H from the periphery of the area where the embossed pattern 41 is formed to the circumferential wall 31 is, for example, 30 mm, but the invention is not limited to the size. The provision of the margin portion 30 around the embossed pattern 41 this way to expose a smooth face, thereby further improving the water drainage of the sink 1.

FIG. 6( a) is a cross-sectional view of the embossed pattern 41 in the horizontal direction x, and FIG. 6( b) is a cross-sectional view in the vertical direction y. As shown in FIGS. 6( a) and 6(b), the projections 25 have a hemispherical shape whose diameter can be set in a range of, for example, 1.0 to 2.0 mm. A hydrophilic film 28 may be laminated on the surface of the embossed pattern 41 forming area at the bottom face 42. The hydrophilic film 28 can be replaced with anything which can allow the surface of the material for the sink 1 to be subjected to surface finishing with good stain removing performance; for example, a surface-active agent may be applied to the embossed pattern 41 forming area, ceramics material may be sprayed thereon, or a silica film may be formed thereon.

A translucent film like a silica film may be used as the hydrophilic film 28. This can permit the texture of the stainless steel plate to appear and improve the cleanness. Further, as the surface finishing with good stain removing performance to be subjected to the surface of the embossed pattern 41, a water-repellent process, an oil-repellent process and other dust-freeing processes can be used in addition to the hydrophilic process. Further, those processes can be combined.

Forming the embossed pattern 41 with such a shape at the bottom face 42 of the sink 1 can bring about the following effects.

When various kinds of tableware, vessels and the like to be washed in the sink 1 to which the invention is adapted come in contact with the embossed pattern 41, abrasions made by the contact are put on the projections 25 of the embossed pattern 41. As the projections 25 of the embossed pattern 41 are formed at predetermined intervals and are non-continuous, the abrasions to be put on the projections 25 also become non-continuous, resulting in that the abrasions can be made visually less noticeable.

Because the projections 25 have the hemispherical shape whose diameter is of the millimeter order, so that tableware, vessels and the like contact with the embossed pattern 41 at a single point of the surface of each projection 25, and do not have line or surface contact with the surfaces of the projections 25. Even if tableware, vessels and the like are in line contact or surface contact with the entire embossed pattern 41, they are in point contact with each projection 25 from the microscopic view. Accordingly, abrasions are discretely formed like dots, and become visually less noticeable. Because the diameter of the projections 25 is in the millimeter order, they can sufficiently support the weight of tableware, vessels and the like, if applied thereto.

The sink 1 has an excellent property even from the viewpoint of removability of deposited stains. Generally, the removability of stains on the sink is improved as the surface does not have irregularity and becomes smoother. From the viewpoint of stain removability, therefore, it is desirable that the bottom face 42 of the sink 1 be formed only by the smooth flat portions 26 without the projections 25.

Therefore, the sink 1 to which the invention is adapted has the flat portions 26 as the basis and has the minimum necessary projections 25 formed from the viewpoint of making abrasions less noticeable. That is, the interval between the projections 25 adjoining in the horizontal direction x (horizontal length Lx of the flat portions) as shown in FIG. 6( a) and the interval between the projections 25 adjoining in the vertical direction y (vertical length Ly of the flat portions) as shown in FIG. 6( b) is made longer than a diameter W of the projections 25. This makes it possible to make abrasions formed by contact of tableware, vessels and the like via the projections 25 less noticeable while demonstrating the best stain removing performance. As mentioned above, the lamination of the hydrophilic film 28 on the embossed pattern 41 can further improve the stain removability.

Next, a description will be given of the influence of the size, layout, etc. of the projections 25 forming the embossed pattern 41 on abrasiveness originated from tableware, vessels and the like, stain cleaning property, and durability.

Given that the height of the projections 25 at the bottom face 42 is H, the distance between tops 25 a of two projections 25 adjoining in the horizontal direction x (horizontal pitch) is Px, and the distance between tops 25 a of two projections 25 adjoining in the vertical direction y (vertical pitch) is Py, the horizontal flat portion length Lx and the vertical flat portion length Ly are respectively acquired as differences between the horizontal pitch Px and the vertical pitch Py and the diameter W of the projection 25.

When the height H of the projection 25 is smaller than 0.05 mm, the durability may be degraded significantly. When the horizontal flat portion length Lx or the vertical flat portion length Ly is shorter than 2 mm, the cleaning property may be degraded. Further, when the height H of the projection 25 exceeds 1.0 mm, or when the horizontal flat portion length Lx or the vertical flat portion length Ly exceeds 10.0 mm, tableware, vessels and the like are caught by the projections 25 more easily.

Accordingly, it is desirable that height H of the projection 25 of the embossed pattern 41 in the sink 1 to which the invention is adapted be set to 0.05 to 1.0 mm, and at least one of the horizontal flat portion length Lx and the vertical flat portion length Ly be set to 2.0 to 10.0 mm. This makes it possible to further improve the cleaning property and durability as compared with a case where the embossed pattern 41 is not formed.

The height H of the projection 25 of the embossed pattern 41 of the sink 1 to which the invention is adapted, the horizontal flat portion length Lx and the vertical flat portion length Ly are not limited to the aforementioned ranges; for example, the height H of the projection 25 may be set in a range of 0.05 to 0.15 mm and the horizontal flat portion length Lx and the vertical flat portion length Ly may be in a range of 2.0 to 3.0 mm. This makes it possible to significantly improve the abrasiveness, cleaning property and durability as compared with the conventional sink which does not have the embossed pattern 41 formed.

In this case, the combination (H, Lx, Ly) of the height H (mm) of the projection 25, the horizontal flat portion length Lx (mm) and the vertical flat portion length Ly (mm) can be set to, for example, (0.05, 3.0, 3.0), (0.05, 2.5, 2.5), (0.05, 2.0, 2.0), (0.1, 2.5, 2.5), (0.1, 2.0, 2.0) or (0.15, 3.0, 3.0). Even such a combination makes it possible to further improve the abrasiveness, cleaning property and durability as compared with the conventional sink which does not have the embossed pattern 41 formed. Even when the height H of the projection 25, the horizontal flat portion length Lx and the vertical flat portion length Ly have some allowances, they can bring about nearly the same effects as obtained in the case of the aforementioned sizes.

Although the description of the embodiment has been given of the case where the horizontal flat portion length Lx and the vertical flat portion length Ly are equal to each other, the invention is not limited to this case, and similar effects are obtained even when the horizontal flat portion length Lx and the vertical flat portion length Ly differ from each other as long as they are in the aforementioned ranges. The vertical direction y and the horizontal direction x need not be strictly the horizontal direction and the vertical direction for the user, and the interval between the projections adjoining at least in one direction has only to be 2.0 to 10.0 mm in the surface protection structure of the invention. Further, the cleaning property and durability of the member surface can be improved further by also setting the interval between the projections adjoining in a direction orthogonal to that one direction to 2.0 to 10.0 mm.

In the embossed pattern 41 of the sink 1 to which the invention is adapted, the projections 25 are arranged adjacent to one another not only in the horizontal direction x and the vertical direction y but also in an oblique direction in which case it is preferable that the distance between the projections 25 adjoining in the oblique direction (oblique-directional flat portion length La) be shorter than the horizontal flat portion length Lx and the vertical flat portion length Ly. Specifically, it is desirable to set the oblique-directional flat portion length La less than 2.0 mm, and when the embossed pattern 41 has a zigzag pattern as shown in FIG. 5( a), for example, the horizontal flat portion length Lx and the vertical flat portion length Ly can be set to 2.5 mm and the oblique-directional flat portion length La can be set to 1.33 mm. Setting the oblique-directional flat portion length La less than 2.0 mm can further improve the abrasiveness and durability.

The embossed pattern 41 is not limited to a case where it is formed on a stainless steel plate which is adapted to the sink 1 of the system kitchen 2, but it can be adapted to various kinds of kitchen members. For example, provision of such an embossed pattern 41 on the top plate 13 can make abrasions put on the top plate 13 themselves less noticeable. Forming the embossed pattern 41 on a stainless steel plate which is used for a lid to be provided at the drain 14 b in the sink 1 can make abrasions on the lid visually less noticeable. Further, it can be adapted to a wash bowl, water-proof pan, bathtub and the like in a bathroom beside kitchen members, and forming the embossed pattern 41 on them make abrasions to be formed on their surfaces less noticeable.

That is, the embossed pattern 41 may be formed on any water-depositable member surface, so that the member surface where the embossed pattern 41 is formed can be protected effectively. The material for the member where the embossed pattern 41 is formed is not limited to the aforementioned stainless steel, but may be any material, such as plastic and artificial marble.

Although the description of the embodiment has been given of the case where the projections 25 forming the embossed pattern 41 have a hemispherical shape as an example, the invention is not limited to the shape. That is, the projections 25 may be formed into any shape as long as they protrude at least from the bottom face 42. Each projection 25 may of course be formed into any shape as long as it contacts tableware, vessels and the like at one point.

EXAMPLE

Referring to an example of the invention, the effects of the invention will be specifically described below. In this example, the embossed pattern 41 with the projections 25 shown in FIGS. 6( a) and 6(b) whose height is 0.05 mm, 0.1 mm or 0.15 mm and with the horizontal flat portion length Lx and the vertical flat portion length Ly being 2.0 mm, 2.5 mm or 3.0 mm was formed in the sink 1 shown in FIG. 3. At that time, the horizontal flat portion length Lx and the vertical flat portion length Ly were made equal to each other. The horizontal flat portion length Lx and the vertical flat portion length Ly together will be hereinafter called flat portion length L. When the combination of the height H (mm) of the projection 25 and the flat portion length L (mm) is defined as (H, L), six embossed patterns 41 with the following combinations of (0.05, 3.0), (0.05, 2.5), (0.05, 2.0), (0.1, 2.5), (0.1, 2.0) and (0.15, 3.0) were used as samples for evaluation and evaluated from the viewpoints of the abrasiveness, cleaning property and durability.

For the evaluation on abrasiveness, three tests were conducted: a test A where a ceramic plate was placed on each embossed pattern 41 and was dragged and turned in a circle five times after which abrasions formed on each embossed pattern 41 were visually judged, a test B where a frying pan was placed up side down on each embossed pattern 41 and was reciprocally dragged five times after which abrasions formed on each embossed pattern 41 were visually judged, a test C where a ceramic bowl was placed on each embossed pattern 41 and was dragged in a circle to be turned five times after which abrasions formed on each embossed pattern 41 were visually judged. Then, abrasiveness of each embossed pattern 41 was evaluated by systematically comparing the results of the visual judgments of the tests A to C.

With regard to the evaluation of cleaning property, first, the area of 40 mm vertical and 40 mm horizontal on the surface of each embossed pattern 41 was filled with oil ink like a magic marker, and left for one hour. Next, the area of each embossed pattern 41 which was filled with oil ink was scrubbed with a net sponge under a load of 500 g. At this time, the net sponge was reciprocated three times while feeding water into the sink 1 from the cock 17 shown in FIG. 3. Then, the cleaning property was evaluated by visually judging the amount of the oil ink remaining on the area of each embossed pattern 41 which was filled with oil ink.

Further, the durability was evaluated by the number of wears until visible abrasions are formed on the bottom face 42 by tableware, vessels and the like. Specifically, a ceramic bowl was placed on each embossed pattern 41 and was reciprocally dragged. Then, the number of reciprocations of the ceramic bowl on the embossed pattern 41 was defined as the number of wears, and the number of wears until visible abrasions appeared on the bottom face 42 was measured for each sample. When the number of wears until the appearance of visible abrasions is large, it means that abrasions are not noticeable unless the projections 25 are worn due to tableware, vessels and the like having made a considerable number of contacts therewith, and the durability is said to be high. When the number of wears until the appearance of visible abrasions is small, on the other hand, it means that abrasions are noticeable even when tableware, vessels and the like have made contacts few times, and the durability is said to be low.

The above results are shown in Table 1 below. For reference, Table 1 also shows the results of similar evaluation on the conventional sink where the embossed pattern 41 is not formed. The evaluation results shown in the Table 1 indicate that the smaller the score, the better the result.

TABLE 1 Shape Height (mm) Flat portion length (mm) Conventional sink Evaluation Abrasiveness Test A small none none none none none Test B large none none none none none Test C large large large large large medium Total of the evaluation scores a evaluation of abrasiveness at concavo portion Cleaning property b visual judgment of amount of magic marker remained small small medium medium large large Durability c Evaluation (higher numerals mean more excellent result) Total evaluation (a + b + c) not considering the design

As shown in Table 1, with the height H being 0.05 mm, nearly the same results on the abrasiveness and durability were obtained for the samples with the flat portion lengths L of 2.0 mm and 2.5 mm. That is, no abrasions were observed in the visual judgments in the test A and the test B, whereas large abrasions were observed in the test C.

With the flat portion length L of 3.0 mm, by way of comparison, small abrasions were observed in the visual judgment in the test A, whereas large abrasions were observed in the test B and the test C. As a result, the total evaluation score on abrasiveness was 18 points for the flat portion length L of 3.0 mm, whereas the total evaluation score was 8 points for the flat portion length L of 2.0 or 2.5 mm, resulting in a considerable difference between the cases.

The difference can be explained to be caused due to the following reason. As the flat portion length L becomes smaller to 2.5 mm and 2.0 mm, the interval between the adjoining projections 25 becomes smaller, so that while the number of the projections 25 per unit area which contact tableware, vessels and the like that are dragged on the embossed pattern 4, the area of the tableware and the like which directly contact the bottom face 42 becomes smaller. If the tableware, vessels and the like directly contact the flat portions 26 of the bottom face 42, abrasions become continuous, whereas for the samples with the flat portion length L lying in the range of the invention, the projections 25 can support most of the tableware, vessels and the like to be in contact therewith. Because the projections 25 have a hemispherical shape whose diameter is on the millimeter order, those tableware, vessels and the like are in point contact with one point on the surface of each projection 25, so that abrasions are dispersed like dots and become visually less noticeable.

When the flat portion length L is 3.0 mm, by way of comparison, the interval between the projections 25 becomes greater and the number of the projections 25 per unit area decreases. As a result, tableware, vessels and the like directly come in line contact or surface contact with the flat portions 26 of the bottom face 42, and abrasions formed thereby become continuous on the bottom face 42 and visually noticeable.

Next, the results of evaluation on the cleaning property will be described. When the flat portion length L is set to 3.0 mm and 2.5 mm with the height H of the projection 25 being 0.05 mm, both of the evaluation scores were 1 point, providing good results. When the flat portion length L is set to 2.0 mm, by way of comparison, the evaluation scores became 3 points, and it was observed that the cleaning property was slightly reduced. That is, as the interval between the adjoining projections 25 becomes greater as in the cases where the flat portion length L is 2.5 mm and 3.0 mm, the fibers of the net sponge becomes easier to pass through the clearance between the projections 25, i.e., on the flat portions 26, it is possible to efficiently remove stains deposited on the flat portions 26. When the flat portion length L is 2.0 mm, by way of comparison, the interval between the projections 25 becomes smaller so that it becomes harder for the fibers of the net sponge to pass through the clearance between the projections 25, thus making it difficult to remove stains deposited on the flat portions 26.

The evaluation results on abrasiveness and durability in the case where the height H of the projection 25 was 0.2 mm were approximately the same for the samples with the flat portion lengths L of 2.0 mm and 2.5 mm. That is, no abrasions were observed at all in the visual judgments in the test A and the test B, whereas large abrasions were observed in the test C.

The cleaning property became lower as the flat portion length L became 2.5 mm and 2.0 mm. The reason therefor is that as the interval between the adjoining projections 25 becomes smaller, the fibers of the net sponge becomes harder to pass through the clearance between the adjoining projections 25. The reason why the cleaning property generally becomes lower as compared with the case where the height H of the projection 25 is set to 0.05 mm is that as the height H of the projection 25 becomes greater, it becomes harder for the fibers of the net sponge to reach the bottom face 42, thus making it difficult to remove stains deposited thereon.

It was observed that the durability with the height H of the projection 25 being set to 0.1 mm was improved as compared with the case where the height H was set to 0.05 mm. This is because the amount of wearing needed for visible appearance of abrasions becomes larger as the height of the projections 25 becomes greater.

In the case where the height H of the projection 25 was set to 0.15 mm and the flat portion length L was set to 3.0 mm, better results were obtained for the abrasiveness as compared with the cases where the height H of the projection 25 was set to 0.05 mm and 0.1 mm. That is, large abrasions were not observed even in the test C, most of abrasions formed by contact with tableware, and vessels and the like were nearly entirely supported at a single point on the surface of each projection 25, making the abrasions less noticeable.

From the viewpoint of cleaning property, however, it was found that the cleaning property was impaired as compared with the cases where the height H of the projection 25 was set to 0.05 mm and 0.1 mm. When the height H of the projection 25 is set to 0.15, however, the work-hardening increases the strength, thereby further improving the durability.

Next, a durability test was conducted as an additional test. FIG. 7 is a graph showing the relationship between the height H of the projections 25 and the durability with the number of wears taken on the horizontal axis and the height H of the projections 25 taken on the vertical axis. In this additional test, a ceramic ware was placed on the embossed pattern 41 formed by the projections 25 with the height H of 0.06 mm, the bottom of the ceramic ware was reciprocally dragged, and a change in the height H of the projection 25 with respect to the number of wears was measured. At the time of reciprocation, a load of 3 kg was applied to the ceramic ware from above. As a result, as shown in FIG. 7, the height H of the projection 25 became 0.048 mm for the number of wears of 80, and the height H became 0.043 mm for the number of wears of 160. Further, it was found that visually observable abrasions would appear when the height H of the projection 25 became smaller than 0.048 mm.

Accordingly, it was observed that when the height H of the projection 25 was set to 0.1 mm and 0.15 mm, a considerable amount of wearing would be needed until the height H of the projection 25 reached 0.048 mm. In other words, it is understood that visible abrasions does not become noticeable even when a considerable amount of wearing is caused by contact with tableware, vessels and the like, and the durability can be improved further. When the height H of the projection 25 is set to 0.05 mm, slight wearing causes the height H of the projection 25 to reach 0.048 mm, so that visible abrasions become noticeable and the durability itself decreases.

The following are the summary of the abrasiveness, cleaning property and durability evaluated in the above manner. As shown in the Table 1, it was understood that when the height H of the projection 25 was set to 0.1 mm and the flat portion length L was set to 2.5 mm, and when the height H of the projection 25 was set to 0.15 mm and the flat portion length L was set to 3 mm, the abrasiveness, cleaning property and durability scored 7 points in both cases and those properties showed the most excellent characteristics. Further, the individual characteristics of each sample evaluated could be improved considerably as compared with the conventional sink. Note that the general beauty (design) of the embossed pattern 41 is excluded from the general evaluation.

As described above, it was experimentally confirmed that the formation of the embossed pattern 41 on the bottom face 42 in the sink to which the invention was adapted hardly influenced the flowability and the sink of the invention was excellent particularly in the flowability of oil as compared with the conventional sink.

Next, the influence of the presence/absence of the lamination of the hydrophilic film 28 shown in FIGS. 6( a) and 6(b) on the abrasiveness and cleaning property was checked. The results are shown in Table 2 below. Table 2 also shows the evaluation results of the conventional sink in which the embossed pattern 41 is not formed.

TABLE 2 Cleaning property Abrasiveness Easy flowing with running water Easy removing stain with sponge Stain remained Hardly abrasive Abrasion less noticeable Conventional sink (oil NG) Conventional sink + hydrophilic film 28 Sink 1 (Present invention) (oil NG) Sink 1 (Present invention) + hydrophilic film 28

As shown in Table 2, when the hydrophilic film 28 was not laminated on the bottom face 42 of the sink 1, the abrasiveness could be improved as compared with the conventional sink while the cleaning property was hardly improved. When the hydrophilic film 28 was laminated on the bottom face 42 of the sink 1, the abrasiveness as well as the cleaning property could be improved considerably as compared with the conventional sink. Similar evaluation was conducted on the conventional sink with the laminated hydrophilic film 28, and resulted in that while the cleaning property could be improved, the abrasiveness could not be improved. The above results showed that to improve both the abrasiveness and cleaning property, it was necessary to apply the hydrophilic film 28 to the bottom face 42 of the sink 1 to which the invention was adapted.

FIG. 7 HEIGHT OF THE PROJECTION 25 (mm) NUMBER OF WEARS (TIME)

TABLE 1 SHAPE HEIGHT (mm) 0.05 OR 0.1 0.05 0.1 FLAT PORTION LENGTH (mm) — 3 2.5 2 2.5 EVALUATION ABRASIVENESS TEST A — 6 1 1 1 (SMALL) (NONE) (NONE) (NONE) TEST B — 6 1 1 1 (LARGE) (NONE) (NONE) (NONE) TEST C — 6 6 6 6 (LARGE) (LARGE) (LARGE) (LARGE) TOTAL OF — 18  8 8 8 THE EVALUATION SCORES A EVALUATION OF — 6 2 2 2 ABRASIVENESS AT CONCAVO PORTION CLEANING B VISUAL JUDGMENT — 1 1 3 3 PROPERTY OF AMOUNT OF MAGIC (SMALL) (SMALL) (MEDIUM) (MEDIUM) MARKER REMAINED DURABILITY C EVALUATION (HIGHER — 4 4 4 2 NUMERALS MEAN MORE EXCELLENT RESULT) TOTAL EVALUATION (A + B + C) — 1 7 9 7 NOT CONSIDERING THE DESIGN SHAPE HEIGHT (mm) 0.1 0.15 FLAT PORTION LENGTH (mm) 2 3 CONVENTIONAL SINK EVALUATION ABRASIVENESS TEST A 1 1 7 (NONE) (NONE) TEST B 1 1 7 (NONE) (NONE) TEST C 6 1 7 (LARGE) (MEDIUM) TOTAL OF 8 3 21 THE EVALUATION SCORES A EVALUATION OF 2 1 7 ABRASIVENESS AT CONCAVO PORTION CLEANING B VISUAL JUDGMENT 5 5 0 PROPERTY OF AMOUNT OF MAGIC (LARGE) (LARGE) MARKER REMAINED DURABILITY C EVALUATION (HIGHER 2 1 7 NUMERALS MEAN MORE EXCELLENT RESULT) TOTAL EVALUATION (A + B + C) 9 7 14 NOT CONSIDERING THE DESIGN

TABLE 2 CLEANING PROPERTY ABRASIVENESS EASY FLOWING EASY REMOVING ABRASION WITH STAIN STAIN HARDLY LESS RUNNING WATER WITH SPONGE REMAINED ABRASIVE NOTICEABLE CONVENTIONAL 3(OIL NG) 3 3 3 3 SINK CONVENTIONAL SINK + 1 1 1 3 3 HYDROPHILIC FILM 28 SINK 1 3(OIL NG) 4 3 1 1 (PRESENT INVENTION) SINK 1 (PRESENT INVENTION) + 1 2 1 1 1 HYDROPHILIC FILM 28 

1: A surface protection structure for protecting a surface of a sink for a system kitchen, wherein an embossed pattern is formed by a plurality of hemispherical projections protrusively provided on the flat smooth surface of the bottom face of the sink, and the embossed pattern is subjected to surface finishing with good removing property of stains, and each of the projections is in point contact with an object to be contacted. 2: The surface protection structure according to claim 1, wherein tops of the projections have a height of 0.05 to 1.0 mm to the flat smooth surface, and an interval between those projections which are adjoining in at least one direction is 2.0 to 10.0 mm. 3: The surface protection structure according to claim 2, wherein an interval between those projections which are adjoining in another direction orthogonal to the one direction is 2.0 to 10.0 mm. 4: The surface protection structure according to claim 3, wherein an interval between those projections which are adjoining in a direction other than the one direction and the another direction is less than 2.0 mm. 5: The surface protection structure according to claim 1, wherein the sink is made of stainless steel. 6: The surface protection structure according to claim 1, wherein a margin portion with no convexoconcaves is provided in a contiguous area between at least one of a drain and a circumferential wall of the sink and the embossed pattern. 7: The surface protection structure according to claim 6, wherein a film having light transmitting property is formed on the embossed pattern by surface treatment with good removing property of stains. 